Soil adds up

The way soil properties combine can be used to 
mathematically determine soil quality

To most people the quality of a soil is the sum of its physical properties — is it healthy and full of microbes? Does water infiltrate it readily or run off? How much air and water can it provide plant roots? Is it hard for roots or equipment to penetrate?

Robson Armindo, a professor at the Federal University of Paraná in Brazil, wanted to better understand the interactions of soil, air, and water. In an article in the Soil Society of America Journal he details how to.

“It was hard for me to use a generic soil physical quality index without knowing its origin and process,” Armindo said. “This sparked my curiosity to evaluate many other factors in an analysis.”

Soil structure can change depending on the crop, climate, and land use in question. In addition, soils differ greatly over space and time. This variability makes it difficult.

“For example, under conditions of highly irrigated vegetable production, the best soil type may be a sandy soil rather than a clay one,” he says. “The user should consider the purpose, crop type, and climate to classify whether the soil has adequate physical qualities or not.”

Armindo combined this information in mathematical equations. He tested the theory across different soils in Germany, Brazil, and the United States and found it successful.

“By using the information from these equations, a person may decide how to use a particular soil,” Armindo explains. “Once the agronomist or land manager has access to this information, in addition to other physical, chemical, and biological properties, he or she can make a decision about the soil’s best use and management.”

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